Measurement of the mechanical properties of soccer balls using digital image correlation method

There are some features for an approved soccer ball by Fédération Internationale de Football Association (FIFA), such as properties of the material, mass, pressure, stitches, etc. Many of these features up to now have been studied; nevertheless, the mechanical properties of the soccer balls to date have not been well reported. The chief purposes of the current research, hence, were to calculate the mechanical properties of the soccer balls, i.e., linear elastic, nonlinear hyperelastic, and viscoelastic, at two different sizes, including 4 and 5 which are using for football and futsal, respectively. To do this, compressive and stress-relaxation loading were applied to 38 approved soccer balls to quantify the stress–strain as well as reduced relaxation function of the balls. The strain/displacement of the balls was also measured via a high-speed camera using Digital Image Correlation (DIC) technique. The results revealed the mean elastic modulus of 66 and 67 kPa for the football and futsal balls, respectively. In addition, the maximum stresses of the football and futsal balls were 16 and 13 kPa, respectively. The nonlinear mechanical response of the soccer balls were analyzed using hyperelastic material models, i.e., Mooney-Rivlin and Ogden. A Finite Element (FE) model was also developed to verify the hyperelastic data compared to the experimental ones and, remarkably, the numerical data were in consistence with the experimental data. Finally, Prony- series was employed to quantify the viscoelastic properties of the balls. During the game, a soccer ball can reach to a speed of 210 km/h that can damage the human eye; however, the injury detail still has not been studied.     

Crocin improved amyloid beta induced long‐term potentiation and memory deficits in the hippocampal CA1 neurons in freely moving rats

Extracellular beta‐amyloid (Aβ) accumulation and deposition is the main factor, which causes synaptic loss and eventually cells death in Alzheimer's disease (AD). Memory loss and long‐term potentiation (LTP) dysfunction in the hippocampus are involved in the AD. The involvement of crocin, as the main and active constituent of saffron extract in learning and memory processes, has been proposed. Here we investigated the probable therapeutic effect of crocin on memory, LTP, and neuronal apoptosis using in vivo Aβ models of the AD. The Aβ peptide (1–42) was bilaterally administered into the frontal‐cortex using stereotaxic apparatus. Five hours after surgery, rats were given intraperitoneal crocin (30 mg/kg) daily, which repeated for 12 days. Barnes maze results showed that administration of crocin significantly improves spatial memory indicators such as latency time to achieving the target hole and the number of errors when compared to Aβ‐group. Passive avoidance test revealed that crocin significantly increased the step‐through‐latency compared to Aβ‐treated alone. These learning deficits in Aβ‐treated animals correlated with a reduction of LTP in hippocampal CA1 synapses in freely moving rats, which crocin improved population spike amplitude and mean field excitatory postsynaptic potentials (fEPSP) slope reduction induced by Aβ. Neuronal apoptosis was detected by TUNEL assay and the expression levels of c‐Fos proteins were examined by Western blotting. Crocin significantly reduced the number of TUNEL‐positive cells in the CA1 region and decreased c‐Fos in the hippocampus compared to Aβ‐group. In vivo Aβ treatment altered significantly the electrophysiological properties of CA1 neurons and crocin further confirmed a neuroprotective action against Aβ toxicity.     

Neurologic emergencies: case studies

During the past 2 decades, the world has witnessed a significant improvement in the understanding of the pathogenesis and treatment of neurologic diseases, which presents emergencies. Every day neurologists are consulted for patients who present with neurologic emergencies to the emergency departments. In this article, we present a series of case reports about patients with acute neurologic and psychiatric problems and discuss their management briefly.     

Is High Preprocedural Renal Resistive Index Sensitive Enough to Predict Iodine Contrast-Induced Nephropathy in Patients Receiving Intra-Arterial Iodinate Contrast?

PurposeRenal Resistive Index (RRI) is a newly introduced sonographic index in predicting contrast-induced nephropathy (CIN) development. It has been suggested that RRI > 0.69 should be considered as a risk factor for CIN development. The present study aimed to calculate the predictive value of RRI using a cutoff point of 0.69.MethodsA total of 90 patients who were a candidate for coronary vessels angiography were enrolled in this study. Color Doppler ultrasonography was performed and RRI was measured. Patients were followed up for 48 hours after contrast media exposure for the CIN development. The diagnosis of CIN was based on a 25% relative rise or 0.5 mg/dL absolute rise in creatinine level. The predictive values of RRI were measured using 0.69 as a cutoff point.ResultsOut of 90 patients, CIN developed in 3 patients and 17 patients had preprocedural RRI > 0.69. Of 3 patients with CIN, 1 had RRI > 0.69. Using 0.69 as the cutoff point, the measured sensitivity and specificity of RRI were 33.3% and 83.9%, respectively.ConclusionsRRI > 0.69 is not a sensitive index in predicting the CIN development and cannot be used as an independent factor.     

Long-term changes in body composition after pancreaticoduodenectomy

Background: The Whipple's procedure (WP) is a major operation that adds a further demand on the body's nutritional reserves and therefore body composition after the effect of pancreatic cancer. The aim was to document changes in body composition changes that occur during the first six months after a WP for a pancreatic cancer malignancy. Methods: Twenty‐seven (14 males, 13 females) consecutive WP patients had body composition measured at baseline and then at 2, 5, 14 and 26 weeks after surgery. These included; anthropometric measure (weight, skin folds and arm muscle area (AMA)), total body measures of protein (TBP), potassium (TBK), water (TBW) and fat mass (FM). Changes were compared using repeated measures analysis of variance. Results: Hospital nutritional care maintained TBP and TBK but at 2 weeks there was a loss of FM (P= 0.037). The nadir of weight loss (P < 0.001) occurred at 5 weeks because of losses of protein (P= 0.007), fat (P < 0.001) and potassium (P= 0.045) but not water. Although weight and FM were still significantly less than baseline measures at 26 weeks weight, TBP, TBK and AMA were not significantly different to preoperative values. Conclusions: Although at 6 months, important measures of the metabolically functioning tissue, TBP and TBK, have returned to preoperative values significant losses occurred during the first 3 weeks after discharge from hospital and FM did not return to preoperative values. These results suggest the need to improve post‐discharge nutritional care.